Consumers have an ever greater choice of end-user network-access playback devices that are capable of playing content including but not limited to text, images, audio, two-dimensional (2D) video, and now even three-dimensional (3D) video. These end-user network-access devices or network terminals receive content over an increasing variety of network access technologies over both constrained-media (including, for example, electrical conductors, fiber optics, and waveguides, among others, and combinations thereof) and unconstrained-media (such as, for example, but not limited to: mobile wireless and fixed wireless in various frequency spectrums including visible light, radio frequency or RF, and other wavelengths of electromagnetic radiation, among others, and combinations thereof).
In addition, as a result of various cost structures for transmission systems and network architectures for allocating individual bandwidth to a user or shared bandwidth to a group of users, the bandwidth available to deliver content to each consumer's end terminal often varies. End-user network terminals can playback, display, or produce content in a form consumable by end users through human senses. Common end-user terminals for accessing networks include, for example, personal computers, telephones, televisions, cell phones, stereos, and radios, among others. Further, different end-user terminals are capable of differing levels of content playback fidelity and quality such as the difference between a low-quality compressed voice telephone call and a CD-quality stereo audio or between a 3-inch cell phone video display and a 60+-inch wide-screen TV display. While most end user terminal devices produce output for the human senses of sight and hearing, other types of more specialized terminals produce output for other senses such as but not limited to touch in a refreshable Braille display. Thus, although the common examples described herein will primarily relate to telecommunication of signals of text, audio, and visual data ultimately delivered to the sight and/or sound senses of humans, the signals can also carry information for any other sensory perception.
In addition, end-user terminals have different levels of processing and computing capability to implement processing of received content. For instance, a desktop computer connected to AC electrical power outlet normally has a processor with more computing ability than a cell phone operating off a light-weight rechargeable battery. Thus, a desktop computer generally has more capability to perform additional post-processing after reception of content than would a cell phone.
With so many variations in the capabilities of end-user terminals and in the bandwidth limitations and characteristics of access networks, broadcast or multicast transmission of content often can be more efficient when the source content is converted into one or more appropriate stream formats before transmission to end-user terminals. Then the end-user terminals each receive content that generally is optimized for the terminals' capabilities (usually including but not limited to screen size, audio output, processing speed, etc.). Furthermore, broadcast or multicast content generally is distributed to a multitude of end-terminals, each of which may have different capabilities, but which might be partitioned into groups of end terminals with similar capabilities (e.g., smart cell phones communicating to a 3G cell tower in contrast to large screen TVs with digital CATV service connected to the same headend.)
Broadcasting source content to many different recipient end-terminals with groupings of quality performance and network access bandwidth often can be accomplished more efficiently by converting the source content to multiple output format encodings each one intended to support a singular terminal type or groups of generally similar end terminal devices. Converting a source content format to an alternative output content format is generally known as transcoding. In addition, converting broadcast or multicast content to support heterogeneous individual or groupings of end terminals by transcoding often can be done more efficiently at a centralized location with additional processing power (and with AC or DC line power instead of the energy restrictions of a portable cell phone battery) rather than implementing computational algorithms to convert media content in the end user terminals receiving the media content. However, even centralizing the transcoding computations and operations can be improved to use processing, memory, and hardware resources more efficiently to support the largest number of transcoded streams for the least costs in terms of processing, memory, hardware, power, etc. Thus, there is a need for greater efficiency in systems and methods used to transcode source content signals into one or more output format signals in a way that reduces equipment costs and/or increases transcoding capacity.
Like reference numbers and designations in the various drawings indicate like elements.